EXETER — Merrimack Valley scored once and it was all it needed as the sixth-seeded Pride upset No. 2 seed Lebanon, 1-0, at Bill Ball Stadium Thursday in the Division II field hockey semifinals.

Merrimack Valley will face top-seeded Windham in the finals on Sunday at Beford High School at 2:30 p.m. Windham advanced with a 3-2 overtime win against St. Thomas Aquinas of Dover on Thursday.

Merrimack Valley’s Olivia Thurber scored what would be the game’s only goal when Lily Davis dribbled down the sideline at the 11-minute mark of the first half and centered a pass to Thurber, who was all alone against Lebanon goalie Emily Foster.

Thurber slipped a shot between Foster’s pads to put the Pride up, 1-0.

“It was a beautiful pass, I was in the right spot,” said Thurber of the play by Davis. “We make a great team.”

Two minutes into the second half it appeared Lebanon tied the game with a slap shot off a penalty corner.

But after a conference by the officials, it was ruled the ball did not leave the circle surrounding the goal, as it must on a corner play.

The goal was waved off.

Windham 3, St. Thomas 2: Windham scored with eight seconds remaining in regulation to send the game into overtime before scoring again in OT to avoid an upset.

Courtney Sweeney scored the winning goal 10 minuites into overtime for Windham. Nicole Croteau had sent the game into overtime with a goal in the last seconds of regulation.

Windham put pressure on St. Thomas early, resulting in five straight penalty corners. Taylor Powell scored off the fifth one to put Windham up 1-0 at the 8-minute mark.

But St. Thomas Aquinas responded 7 minutes later with some nifty ballhandling by Jensen Palmer, who was able to split the Jaguar defense and beat Kelsey Frederico in net to the the game at 1-1.

St. Thomas kept applying pressure in the second half before Gabrielle Dodier scored off a long corner and put the Saints in front 2-1, setting up Windham’s late-game heroics.